The present invention relates to an electronic control device.
For example, various types of waterproofing are applied to a casing accommodating an electronic circuit substrate, such as an electronic control device disclosed in Japanese Laid-Open Patent Publication No. 2005-150633. Conventionally, there has been required to effectively utilize a restricted space in a vehicle. Further, a high water resistance is required in the electronic control device for adding to flexibility in the arrangement.
This type of electronic control device is typically arranged in a portion close to a wheel in an engine compartment. Hence, when the vehicle is traveling on a riverbed or a beach, electronic control devices in the engine compartment can get wet with a great amount of water. In such a case, only the conventional waterproofing cannot necessarily provide a sufficient protection. Accordingly, in the electronic control device used under the environment mentioned above, an airtightness in a joint portion between the casing and a lid closing an opening of the casing is secured by using a sealing material (a silicone adhesive agent or the like) in place of a rubber sealing member such as an O-ring or the like.
In the case of the structure mentioned above, in order to stably obtain a high sealing performance, it is important to keep a clearance (an interval) between the casing and the lid constant at least until the sealing material is cured. However, in addition to the fact that a high assembling precision is required, segmented control processes must be performed until the sealing agent is cured after the casing and the lid are assembled. Therefore, the manufacturing costs of the electronic control device employing the structure mentioned above are increased due to the difficulty of the assembling steps and the complicated control processes.